Ruler for blackboards.



P. CRAVHRa RULER FOR BLACKBOARDS..

APPLICATION FILED SEPT.2. 1916.

gpm Patented Jan.' 1, 1918'.

PHILIP? CRAIVIER, OF NEWARK, NEW JERSEY, ASSIGNQR TO MAGDALENA SCI-IAEFER, OF NEWARK, NEW' JERSEY.

RULER FOR BLACKEOARDS.

specification of Letters Patent.

Patented Jan. 1, 1918.

Application filed. September 2, 1916. Serial No. 118,161.

To all whom it may concern Bev it known that I, Prrimrr CRAMER, a subject of the King of Bavaria, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Rulers for Blackboards, of which the following is a specication.

My invention relates to time-saving rulers for chalk-lining blackboards in schools.

The object of my invention is to provide a ruler which can be handled as easily as a plain straightedge, yet contains all the straightedges necessary to draw lines for common writing and likewise for writing of musical notes without having to litt the ruler o" the board.

The accompanying drawings will make this clear.

c Figure 1 is a top view of my ruler showing principally the two ends and showing how ytwo sets of ruling bars arek connected by links to two middle-pieces.

Fig. 2 is a top view ot' one of the middlepieces.

F ig.v3 is aside view of the same showing they links in end view.

Fig. 4 is a fullsize section on line en Fig. l. I

Fig. 5 is a section of the ruler when in its second position.

Fig. k6 is a pl-an ot one set'of chalk-lines as used for common writing. Y

Fig. 7 is a plan of lines used for writing musical notes.

Numerals 1, 2, 3, 4 represent four ruling bars of a T-shaped section, all slidably mounted upon two rods 5 and 6. Bars 1 and 2 are rigidly connected by plates 7 and 8, and bars 3 and 4 are likewise rigidly connected by plates 9 and 10. These two sets of bars are connected by links 11 to two middle-pieces 12. This arrangement gives siX useful ruling edges. The rods 5 and 6 pass each through one middle-piece with space allowed for longitudinal motion for each middle-piece. Moving the middle-pieces in certain directions will bring all links at right angles to the middle-pieces and move the two sets of ruling bars apart, while pushing back of the middle-pieces will bring the ruling bars closer.

4 '1`he spread ruler is used for making four or six lines for common writing and the closed ruler for lines for musical notes.

Each middle-piece has a shoulder 13 which will terminate longitudinal motion by striking against the through-passing rod. This striking is timed to occur just after the center lines of the links have passed the rectangular lines lll as shown in Fig. 1, and to prevent untimely return motion of the middle-pieces two contracting springs 15 and 16 attached to the two sets of ruling bars with a tendency of closing the ruler are employed. The action of the springs would move the links in the directions indicated by arrows 17, which movement is prevented by the shoulders 13 in the middle pieces and it requires torce to close the ruler.

Little rubber feet 18 assist in keeping the ruler from sliding.

The ruler when used is pressed against the board with one hand and the other hand guides the chalk.

rIhe dilierent positions in which the chalk can be held are indicated under numeral 19. Line 20 indicates the surface of the board.

lVhat I claim is:y

l. In a ruler for chalk-lining blackboards, a plurality of ruling bars secured together in pairs, means for normally drawing said pairs together, and means for separating said pairs against the action of the irst mentioned means. Y i

2. In a ruler for chalk-lining blackboards, a plurality of bars secured together in pairs, operating means located between adjacent pairs of bars, and means, connecting said operating means with adjacent pairs of bars whereby said pairs can be drawn together or separated.

3. In a ruler for chalk-lining blackboards, a plurality ot ruling bars secured together in pairs, a plurality of sliding bars located between adjacent pairs of ruling bars, and means connecting said sliding bars and said pairs of ruling bars, whereby said pairs of ruling bars can be drawn together or separated.

il. In a ruler for chalk-lining blackboards, a plurality of ruling bars secured together in pairs, a plurality of sliding bars located between adjacent pairs of ruling bars, and a plurality of spaced links connecting said sliding bars and said pairs of ruling bars whereby the latter may be drawn together or separated.

5. In a ruler for chalk-lining blackboards, a plurality of ruling bars secured together in pairs, means for normally drawing said pairs together, a plurality of sliding bars located between adjacent pairs ofrvrulingY bars, and means connecting said sliding bars and said pairs of ruling bars, whereby the latter can be drawn together or separated.

6. .In a ruler for chalk-lining blackboards, a plurality of ruling bars, secured together in pairs, a spring attached Vto adjacent pairs of ruling bars for no-rniallydrawing 'the same together, a plurality of sliding bars located Vbetween adjacent pairs of ruling bars, and a plurality oit links connecting said sliding bars and said pairs of ruling bars whereby the latter can be drawn together or separated. v l

7. Ina ruler for chalk-lining blackboards, a plurality of ruling bars, means connecting saidbars in pairs, and means located between adjacent pairs ofruling bars for drawing together or separating said pairs of bars.

8. In a vruler for chalk-lining blackboards,

- a plurality of ruling bars, plates connecting said bars inpairs, a plurality of sliding bars located between adjacent pairs of ruling bars, and means connecting said pairs of ruling bars and said sliding bars whereby said pairs of ruling bars canube drawn togethei or separated, v

, 9; In a yruler for chalk-lining blackboards, a plurality of ruling bars, plates connecting said bars in pairs, a plurality of sliding operating bars located between adjacent pairs of ruling bars, and links connecting said sliding bars and pairs'of ruling bars for drawing together and separating said pairs of bars 'upon movement of said 'sliding 0pe'iating bars.

f 10. In a ruler for chalk-lining blackboards, a: plurality of ruling bars, plates connecting said barsnin pairs, rods on which` vsaid barsare mounted to slide, and means for drawing together or separating said pairs ofv bars.

l1. In a ruler for chalk-lining blackboards, a plurality of ruling bars, means connecting said bars in pairs, operating bars located between adjacent pairs ot bars,

means connecting said operating barsand, said pairs of ruling bars, whereby upon'H movement of said operating barssaid'pairs of ruling bars cancbe drawn together or separated, and means 4for limiting the move.-V

ineiit of said operating bars.

12. In aV ruler lfor chalk-lining black-y boards, a plurality of ruling bars, plates connecting said bars in pairs, rods on which said bars are mountedtoslide, and means for drawing together andV separating, said pairs of bars.

13. Ina ruler for chalk-lining blackboards, a plurality of ruling bars, plates .connecting said*y bars in pairs, rods on which said bars are mounted to slide, slidingl opin presence o twoY witnesses.

PHILIPP` CRAMER Witnesses: M. M. DENBrGrI E. L. 'KNUPFER.

separated operating movementV Copies of this patent may be obtained for ve cents each, by addressing the Commissioner -of- Patents,

' f Washington, D. C. i n 'Y of ruling y 

